Vontron 75 GPD membrane for membrane housing. Suitable for Water TDS Level upto 1000 ppm. Membrane will not work for TDS Higher than 1000 TDS. Note - Membrane to be fitted in membrane housing within 5-10 minutes after seal opening. If kept seal opened for more than 5-10 minutes, then membrane will get blocked automatically and will not be useful anymore. After fittings the membrane, Please adjust the tds level according to your requirement by using tds controller. Please ensure that other filters installed in water dispenser or water purifier are new.